The Environmental Protection Agency's hazardous waste ombudsman resigned Monday and has accused the agency of trying to obstruct investigations that could make the EPA and its chief Christine Todd Whitman look bad.

Robert Martin's resignation comes less than a week after inspector general staffers confiscated his files and changed the locks on his office door.

Martin, who took his office more than nine years ago under President George H.W. Bush, had been investigating possible conflict of interest charges between Whitman’s husband and the owners of two Superfund cleanup sites in Colorado and Pennsylvania.

But late last year, Whitman decided to abolish the ombudsman’s office and fold Martin’s job into the EPA’s inspector general’s office, the internal watchdog of the agency. She said it was in response to a government report that said Martin needed more independence.

Backed by at least a dozen members of Congress, Martin, however, said the move was to squelch any ability the ombudsman might have had to independently investigate wrongdoing at the agency.

Martin filed suit in January with a federal judge, who placed a protective order on his office, including the investigative files. The judge rescinded that order last week, ruling that Martin should have exhausted his administrative appeal process before going to the courts.

On Thursday, while Martin was out of town, members of the inspector general’s office began confiscating his files, including the ones dealing with Whitman’s conflict of interest suit.

"The stormtroopers did come in, confiscate all files and that was the end of the ombudsman," said Bruce Kaufman, a senior EPA investigator who was transferred out of Martin's office last year after he first lodged complaints against Whitman for possible conflict of interest.

That was the last straw for Martin, who resigned Monday. He said he was told his new job at the IG office would be to answer phones on the EPA hotline. His title would be stripped and his files opened to IG scrutiny.

"Your communication to the inspector general to seize my files, change my locks, and transfer me immediately to the Office of Inspector General underscores the fact that the inspector general had no actual independence if they proceeded to act at your discretion," Martin wrote to Whitman in his resignation letter.

Whitman's office deferred all comment to the IG's office, which did not return calls by press deadline late Monday.

Word of Martin's resignation drew disappointment from congressional circles, some of which were trying to save Martin's ombudsman job. They said he was a public advocate who had given communities a face and a point person for their grievances and concerns.

"He's the last advocate for the people and if you don't have that, you don't have anything — the EPA could get away with murder and there is nothing you can do about it," decried Eric Schmeltzer, a spokesman for Rep. Jerrold Nadler, D-N.Y., who has joined 11 other Democrats in asking the Office of Special Counsel to take up Martin's case.

Martin's travails haven't just attracted Democratic support. Republican lawmakers whose states have dealt first hand with Superfund sites and the EPA are not too happy with Whitman's decision to strip Martin of his powers.

"We're disappointed that he is leaving — he is a true public servant," said Sean Conway, spokesman for Sen. Wayne Allard, R-Colo., who introduced legislation late last year to empower Martin's office and make him more independent.

"The EPA was putting pressure on him not to pursue with due diligence" cleanup efforts at the Shattuck Chemical Co. Superfund site in Colorado, Conway said.

Martin, who began his investigation of Shattuck during the Clinton administration, found that the EPA reneged on an initial deal to clean up radioactive waste and instead worked out a deal that was more friendly with the polluters.

"Clearly the EPA made the wrong decision and it's costing the taxpayers millions of dollars," said Conway. "There has to be checks and balances. What Sen. Allard envisions is an office where citizens can come to the ombudsman and say this project is not in the best interest of the community and we would like you to look at it."

Martin's office began investigating complaints of a possible conflict of interest in Whitman's office in early 2001.

Earlier this year, Kaufman charged that Whitman falsely stated that the air around the World Trade Center was safe in the days after the Sept. 11 terror attacks, saving millions of dollars for an insurance company owned by Citigroup Inc., which backs a venture capital firm run by her husband, John Whitman.

John Whitman worked for Citigroup for 15 years and owned $100,000 to $250,000 in company shares as of last January. He is now a managing partner of Sycamore Ventures, of which Citigroup is one of its biggest investors.

The ombudsman's office also alleges that the EPA made "sweetheart deals" with Citigroup over the Superfund cleanup sites it owns, including Shattuck Chemical, and an old battery crushing plant in Pennsylvania.

In what critics call a "generous deal," Citigroup agreed to pay $7.2 million to help remove the waste on the Denver site, but experts say it will actually cost $100 million.

Kaufman maintains that Whitman should have recused herself from consideration of the Shattuck case by publicly designating a deputy to handle it late last year.

In January, Whitman's office said there was "absolutely no evidence" Whitman played a role in the Shattuck agreement, which was reached before she came into office and is being handled by an EPA regional office.

This wasn't the first time that Whitman has abolished a watchdog office. As New Jersey governor, she did away with the state's public advocate in 1994.

The Associated Press contributed to this report.